Given a binary tree and a sum, find all root-to-leaf paths where each path's sum equals the given sum.
Note: A leaf is a node with no children.
YouTube
Input:
tree=[5,4,8,11,null,13,4,7,2,null,null,5,1]
sum=22
Output:
[
[5, 4, 11, 2],
[5, 8, 4, 5]
]
Explanation:
Print Palindromic Paths of Binary tree - GFG
Last updated
Was this helpful?
Was this helpful?
// Definition for a binary tree node.
public class TreeNode {
int val;
TreeNode left;
TreeNode right;
TreeNode() {}
TreeNode(int val) { this.val = val; }
TreeNode(int val, TreeNode left, TreeNode right) {
this.val = val;
this.left = left;
this.right = right;
}
}/**
* Time complexity : O(N^2) where N are the number of nodes in a tree.
* Space complexity : O(N)
*/
class Solution {
public List<List<Integer>> pathSum(TreeNode root, int sum) {
List<List<Integer>> resultList = new ArrayList();
if(root == null) return resultList;
helper(resultList, new LinkedList<Integer>(), root, sum);
return resultList;
}
private void helper(List<List<Integer>> resultList,
LinkedList<Integer> currList,
TreeNode node,
int sum) {
if(node == null) return;
currList.add(node.val);
if(sum == node.val && node.left == null && node.right == null) {
resultList.add(new ArrayList(currList));
} else {
helper(resultList, currList, node.left, sum-node.val);
helper(resultList, currList, node.right, sum-node.val);
}
currList.removeLast();
}
}